High powered archery bows, that is, bows and crossbows with high draw weight, must efficiently deliver the substantial stored energy in flexed limbs through the bowstring to the arrow or bolt. The smooth and efficient delivery of the potential energy stored in the flexed limbs to the arrow, to produce kinetic energy in the form of motion of the arrow, is difficult to achieve and usually results in residual energy remaining in the bow system after the arrow's departure that is dissipated in the form of vibration, noise, and in some instances can result in the generation of a bowstring shockwave propagating along the bowstring to the cams of the system causing the bowstring to derail and jump off the cam track. That is, the high forces being transmitted to the bowstring during bowstring release may result in the propagation of a standing wave along the length of the bowstring resulting in the bowstring derailing from the groove of the cam or wheel. These difficulties are particularly acute with crossbows.
It is known in the prior art that the transfer of energy from bowstring to the arrow or bolt may be more efficiently accomplished by adding mass to the bowstring. This addition of mass to the bowstring typically incorporates the clamping of C-shaped brass nock sets to the bowstring on either side of the nock point of the bowstring. These brass nock sets come in a variety of weights and are usually clamped to the bowstring by deforming the brass into a grasping position against the bowstring. It is believed that the addition of the mass somewhat slows the acceleration of the arrow or bolt but the force is more efficiently transferred from the limbs through the bowstring to the arrow. In high powered compound bows, and particularly with crossbows, the violence accompanying the release of the bowstring and the transfer of energy from the limbs to the arrow may result in forces acting upon the weights that cause them to move along the length of bowstring and thus change their position (and the characteristics and effect of the added mass) and in some instances may even be dislodged from the bowstring resulting in a dangerous condition wherein the dislodged weight, traveling at a high rate of speed, may strike the archer or a spectator.
Other types and styles of mass increasing devices have been proposed in the prior art including the utilization of rubber, plastic or other polymer weights in the form of sleeves that are threadedly positioned on the bowstring at strategic locations. These polymer weights grasp the bowstring through the elasticity of the polymer; however, the violence of the release of the bowstring temporarily and radically deforms these polymer weights resulting in the loss of precise positioning of the weight and in some cases destruction of the weight. Further, it is difficult to achieve sufficient mass through the utilization of polymer weights.